Crankshaft undersize FYI
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Laughing Gas
Joined: Nov 2002
Posts: 1,198
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From: Fairmont
Crankshaft undersize FYI
Hopefully you don't mind I would like to say a few things about this idea of undersize being bad. I have had a few phone calls about it and also the recent post.
A number of years ago bearings were designed with it multi layer also with babbit being the top layer. But back then when you ground your crankshaft 10, 20, 30, 40, or what ever, they just made up the difference with a thicker layer of babbit. Well you can see babbit is very soft and a thicker layer would just pound out fast, hence the old saying, "don't grind your shaft past 010". And it probably had some truth back then. Now bearings that are for undersize crank shaft have a thicker steel backing to make up the difference, and will last just great. So my opinion is,if they make a bearing, it is safe.
Some common examples: Chevy ground to the Small journal size from 2.100 to 2.000.
The 400 is offset ground by some companys over .200" one direction.
The 460 has been offsetground .375" one direction for a stroker set-up.
FYI
My 2 cents
A number of years ago bearings were designed with it multi layer also with babbit being the top layer. But back then when you ground your crankshaft 10, 20, 30, 40, or what ever, they just made up the difference with a thicker layer of babbit. Well you can see babbit is very soft and a thicker layer would just pound out fast, hence the old saying, "don't grind your shaft past 010". And it probably had some truth back then. Now bearings that are for undersize crank shaft have a thicker steel backing to make up the difference, and will last just great. So my opinion is,if they make a bearing, it is safe.
Some common examples: Chevy ground to the Small journal size from 2.100 to 2.000.
The 400 is offset ground by some companys over .200" one direction.
The 460 has been offsetground .375" one direction for a stroker set-up.
FYI
My 2 cents
